SDOCTn

SDOCTn, or Spectral-Domain Optical Coherence Tomography nano-enhanced, is a proposed imaging modality that extends conventional SD-OCT by integrating nanoscale light-matter interaction control, ultra-broadband sources, and enhanced computational reconstruction. It envisions achieving higher depth sensitivity and improved axial resolution by exploiting wider spectral bandwidth, more precise dispersion management, and advanced phase-stable detection. The technique relies on spectral-domain interferometry with improved calibration and digital processing to extract sub-nanometer structural information from the interferometric signal and to suppress speckle noise through model-based reconstruction and deep learning.

Potential applications include biomedical imaging where nanoscale features are relevant, such as cellular and subcellular structures in ophthalmology, dermatology, and histology, as well as materials science for characterizing thin films and nanostructures. In ophthalmology, SDOCTn could provide finer delineation of retinal layers and photoreceptor interfaces. In other fields, it could aid in non-destructive testing of microelectronics or coatings.

Advantages of SDOCTn would include higher axial resolution, improved sensitivity to weakly scattering features, and non-invasive, label-free operation. Limitations are primarily technical: the requirement for ultra-broadband and stable light sources, complex dispersion compensation, greater data volumes, higher computational load, and potential sensitivity to motion and sample heating. The concept remains under research and has not become a standard instrument; practical realization would depend on advances in photonics, detection, and reconstruction algorithms.